1. Field
Exemplary embodiments relate generally to sensor shields such as windscreens for microphones or other sensors.
2. Related Art
Working microphones and other sensitive equipment used in the field may require protection from the elements. For example, ultra-sensitive gunfire detection equipment, including the Projectile Detection and Cueing (PDCue®) Tetrahedral and Packbot designs, by AAI Corporation, include microphones which may desirably employ windscreens and analogous equipment.
These windscreens may employ mechanisms for attachment. For example, miniature setscrews may be used to attach the windscreens to microphone posts. Primary disadvantages of using such setscrews includes the fact that a relatively thick structure to hold the setscrew may be required, and a special tool may be needed when attaching and removing windscreens in the field. Such special tools are readily misplaced and may be difficult to obtain in certain remote areas, particularly in combat and other demanding conditions. Tiny setscrews are easily damaged, often lost, and may be difficult to replace in the field.
Some related technologies have made use of simple, plastic cable ties to hold the windscreens in place. An obvious disadvantage to using plastic cable ties in the field is their poor resistance to sunlight, unless the plastic is pigmented black, and/or ultraviolet inhibited. Furthermore, most plastic ties are not reusable, and have to be cut off and discarded when changing a windscreen. In addition, cable ties are only applicable to relatively narrow-shaped, elongated windscreens, since larger ball-shaped windscreens would have no such neck for the wire tie to readily attach. For example, although it may be feasible to manufacture a large ball-shaped windscreen having a narrow neck, such a windscreen would be cost prohibitive and highly wasteful of material, and would likely be manufactured in two pieces.
Spring-loaded ball lock devices are available to provide a snap-lock feature. However, ball locks are fairy expensive, and require substantial housings for proper installation. Furthermore, a ball lock by itself would not provide any positive over travel limit. A windscreen that is installed beyond its optimum sweet spot, may allow the windscreen material to physically touch the surface of the microphone. Should the windscreen touch the surface of the microphone, then unwanted noise could easily be generated, by inadvertent contact and rubbing of the two surfaces, especially under the influence of dynamic motion and/or windy conditions.
Finally, most windscreens on the market merely rely upon the frictional fit between the resilient windscreen material and the microphone to hold them in place. A frictional interface is not considered reliable when subjected to the external forces of high wind and rain, jolting over rugged terrain, or in the presence of rough handling environments such as inadvertent contact with foliage and brush when mounted on a moving vehicle, as expected in many military environments.
Furthermore, the use of frictional, drawstring, or cable tie type attachments do not provide a positive means to achieve axial location of the windscreen along the microphone's stem. Knowing that it is highly desirable for acoustic reasons to not bottom the windscreen directly against the microphone, as mentioned above, the lack of a positive positioning feature can be deleterious to the microphone's desired performance.
What is required is a method and system for quickly removing and attaching a windscreen used for a microphone that compensates for the above mentioned disadvantages and solves these problems, and improves the state of technology for windscreen retention generally.